The present disclosure relates to a system and method for providing controlled soil moisture conditions within potted plants in a large-scale, automated gravimetric screening system, typically located in a greenhouse.
The gravimetric method is a known technique of imposing a precision drought stress regime on plants growing in containers or pots by measuring changes in the mass of the pot. Measuring the pot mass provides an accurate calculation of changes in soil moisture, and rewater values are determined by calculating the difference between the actual water content and the desired water content based on a predetermined water deficit program. With appropriate control of evaporative water loss from the soil, the gravimetric method allows for determination of plant transpiration and total plant water use through the duration of an experiment.
Typically, gravimetric screening is a highly labor intensive process that limits throughput and capacity in screening specific programs. Conventional screening systems move individual pots to a weighing and re-watering station. In some cases, entire blocks of plants are moved as a unit to another location for weight measurements and re-watering. This movement introduces additional confounding effects to testing procedures such as vibrations during movement and low density growth conditions, for example, which are not typical in field environments. These known gravimetric screening systems do not make the most efficient use of greenhouse space.
The automated gravimetric screening system and method of the present disclosure provides a high throughput greenhouse screening system using a support platform and pot design that maintains the plants in a static location during the testing. The system includes a lower gantry located below the support platform which has a plurality of independent load cell modules and plumbing to weigh and supply water to each row of pots. In an illustrated embodiment, each row of pots is lifted simultaneously by the load cell modules to acquire weights, calculate how much water should be added to bring the pot to a desired mass, and then supply water to the pot based on the calculation. The lower gantry is aligned with each row of pots as it moves along the length of the support platform. An entire row of pots is illustratively weighed and re-watered simultaneously within a matter of minutes without moving the pots to a separate weighing station. By weighing and re-watering the pots from beneath the platform, the present system and method permits a high-speed automated upper gantry to capture high resolution images, temperature data, or other sensor data to quantify the plant stress level or plant canopy characteristics during the experiment.
The present system and method provides reduced noise and a more uniform and precisely controlled water stress environment for both well-watered and drought treatment groups. Improved control enables the comparison of measured physiological parameters with greater confidence as water stress is equal and uniform across the experiment.
The platform and gantry system illustratively uses a customized pot designed to work with the lower gantry positioned under the support platform for weighing and re-watering the pots. The illustrated pots enable re-watering from below the soil surface. Each pot illustratively includes a reservoir system configured to hold water therein. The reservoir system surrounds the soil column defined by the pot from a location just below a top surface of the soil to the bottom of the pot. An illustrated embodiment provides fluid communication from the reservoir system to soil is provided via a plurality of vertical fluid channels that extend along an internal circumference of the pot. In an illustrated embodiment, a synthetic fabric mesh covers the channels to prevent root and dirt debris accumulation in the channels of the reservoir. Water and/or nutrients are illustratively delivered into the reservoir through a load cell module and through a check valve located at the bottom of the pot. Upon contact with a support surface of a load cell module, an o-ring on the pot forms a seal around the check valve to reduce water loss. The pots deliver precise amounts of water to the soil column and result in healthy plant material with acceptable growth and development.
In one illustrated embodiment of the present disclosure, a system is provided for controlling soil moisture in a plurality of potted plants to perform water deficit experiments. The system includes a stationary platform having a plurality of openings formed therein. The openings are located in a plurality of rows on the platform. The system also includes a plurality of pots located in the plurality of openings in the platform. The pots are supported by the platform. A movable lower gantry is located below the platform. The movable lower gantry supports a plurality of load cell modules aligned with the plurality of pots located in a row of openings. Each load cell module includes a load cell having a support movable from a retracted position spaced apart from a bottom surface of a pot to an extended position in which the support of the load cell lifts the pot upwardly to support the weight of the pot thereon so that the load cell weighs the lifted pot. The system further includes a controller coupled to the load cell. The controller is programmed to determine whether the pots need watering based on the weights of the pots and the water deficit experiment. The system still further includes a water supply coupled to the load cell module. The water supply includes at least one flow control valve controlled by the controller to selectively supply water through the load cell module to the pot.
In an illustrated embodiment, the system further includes an upper gantry movable above the platform. The upper gantry including at least one sensor located thereon to acquire data related to the plants in the plurality of pots. Illustratively, the sensor is a camera to take images of the plants in the plurality of pots, a temperature sensor, or other sensor.
In another illustrated embodiment of the present disclosure, a method is provided for controlling soil moisture in a plurality of potted plants to perform water deficit experiments. The method includes providing a stationary platform having a plurality of openings therein, and locating a plurality of pots in the openings of the platform. The pots are supported by the platform. The method also includes lifting the pots with the plurality of load cell modules, weighing each of the plurality of pots with the load cell modules, determining whether the pots need to be watered based on the weight of the pots and the water deficit experiment, watering the pots through the load cell modules, if necessary, based on the determining step, and lowering the plurality of load cell modules so that the plurality of pots are supported by the platform.
In an illustrated embodiment, the openings in the platform are located in a plurality of rows. The step of moving a plurality of load cell modules under the platform aligns the load cell modules with a row of pots, and the step of lifting the pots lifts an entire row of pots with the plurality of load cell modules simultaneously. The method also includes moving the load cell modules to a next row of pots and performing the lifting, weighing, determining, watering, and lowering steps for the next row of pots.
In yet another illustrated embodiment of the present disclosure, a pot is provided for use with system for controlling soil moisture in a plurality of potted plants to perform water deficit experiments. The system includes a stationary platform having a plurality of openings formed therein. The pot includes a body portion having an open top end and a bottom end, and a flange coupled to the body portion adjacent the top end. The flange is configured to engage the platform to hold the body portion within an opening of the platform. The pot also includes a fluid reservoir having a bottom portion located adjacent the bottom end of the body portion, a plurality of vertically extending fluid channels extending upwardly toward the top end of the body portion, and a fill opening located at the bottom end of the body portion in communication with the bottom portion of the fluid reservoir. The pot further includes a check valve coupled to the fill opening to permit fluid to be supplied to the fluid reservoir from the bottom end of the body portion through fill opening and the check valve.
In an illustrated embodiment, the pot includes a mesh forming an inner portion of the vertically extending fluid channels. The mesh permits fluid to flow through the mesh to soil within the body portion, but preventing soil debris and plant roots from accumulating in the vertically extending fluid channels of the reservoir.
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure. The exemplification set out herein illustrates embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.